Electric cooking utensil



April 13, 1954 H. STILES ELECTRIC COOKING UTENSIL 2 Sheets-Sheet 1 FiledJune 24, 1950 I r INVENTOR. fix yliz'lea 2 Sheets-Sheet 2 Filed June 24,1950 Patented Apr. 13, 1954 UNITED STATES PATENT OFFICE ELECTRIC COOKINGUTENSIL Harry L. Stiles, Bridgeport, Conn.

Application June 24, 1950, Serial No. 170,228

7 Claims. 1

This invention relates to cooking appliances and more particularly toself contained portable cooking appliances.

It is an important object of the present invention to provide animproved cooking appliance which is adapted for use in various types ofcooking operations; more specifically it is an object of the presentinvention to provide a cooking appliance of the type set forth havingheating elements which form a part of the appliance, certain of theelements being removable or inoperative during certain types of heatingoperations.

Another object of the invention is to provide in a cooking utensil ofthe type described an improved mounting for the heating elements andimproved supports for the cooking utensils to be used in cooperationwith the heating elements.

Yet another object of the invention is to provide in a cooking applianceof the type described an improved mounting for a thermostat controlwhereby the control gives different types of desired responses dependingupon the type of cocking to be performed.

Still another object of the invention is to provide in a cookingappliance of the type set forth an improved base structure wherein meansis provided for maintaining the base structure and particularly thatportion of the base structure which rests upon the supporting surface ata relatively low temperature whereby to prevent the supporting surfacefrom being marred and to prevent the user's body from being burned bycoming in contact therewith.

A further object of the invention is to provide a cooking appliance ofthe type described which is more economical to fabricate and operate andwhich is readily converted for use in various types of cookingoperations.

These and other objects and advantages of the invention will be betterunderstood when taken in connection with the following description andthe accompanying drawings. 4

In the drawingsiwherein like reference numerals have been used todesignate like parts throughout:

Figure 1 is a side elevational view of a cooking appliance made inaccordance with and embodying the principles of the present inventionwith the dome positioned thereon;

Figure 2 is an exploded view showing certain of the parts of the cookingappliance which form the subject matter of the present invention inperspective;

Figure 3 is a cross sectional view of the cook- 2. ing appliance shownin Figure 1 substantially as seen in the direction of the arrows alongthe line 3-3 of Figure 1;

Figure 4 is a partial plan view of the dome forming part of the presentinvention showing a temperature indicating device mounted thereon in theaperture formed by the removal of one of the heating elements;

Figure 5 is an enlarged cross sectional view of the cooking applianceshown in Figure 1 substantially as seen in the directions of the arrowsalong the line 55 of Figure 1, the appliance being shown in conditionfor broiling;

Figure 6 is a partial cross sectional view similar to Figure 5 showingthe lower heating element and the heating spreader plate used inroasting and baking in the operative position;

Figure 7 is a view similar to Figure 6 showing a grill in position overthe lower heating element to be used in direct grilling and fryingapplications;

Figure 8 is a perspective view reduced in size showing the underside ofthe grill illustrated in Figure 7; and

Figure 9 is a further enlarged view in vertical cross section of thejuncture of the base, the lower heating support, and the dome.

Referring now to the drawings and more particularly to Figures 1 and 2thereof, there is shown a cooking appliance, generally designated by thenumeral 10, made in accordance with and embodying the principles of thepresent invention. The appliance in comprises generally a cover or dome[2, a removable upper heating elemerit I 4, a heater spreading plate [6,a lower'heating element I8, a heating element support plate 20, an innerlining 22, and an external housing 24.

The heating element support plate 20, the inner lining 22, and theexternal housing 24 are assembled to form a doubled wall base whichserves as a support for the lower heating element 18, the dome l2, andthe other associated parts to be described hereinafter.

As is best shown in Figures 2, 3, and 5, the external'housing 24 isgenerally cylindrical in shape and includes a circular bottom 26 and anupstanding circumferentially extending wall 28. A plurality of apertures30 are formed in the bottom 26 and are arranged in a circle near theouter periphery of bottom 26. Another series of apertures 32 is formedin the circumferentially extending wall 28 of housing 24 adjacent theupper edge thereof. Apertures 32 cooperate with the apertures 38. in amanner and for a purpose to be described more fully hereinafter. Aplurality of 3 depending legs 84 are provided to space the bottom 26 ofhousing 24 away from the supporting surface 36. A recess 38 is formed onthe lower side of legs 34 and receives the head 48 of a threaded bolt 42which extends through one of the apertures 38 in bottom 26. Bolt 42receives on the threaded end thereof a nut 44 whereby to fasten leg 34to the bottom of housing 24. The legs 34 are preferably formed ofmaterials which do not conduct heat or which are generally referred toas heat insulating materials. Suitable examples of such material arewood, fiber, and plastics. By forming the legs 34 of a non-conductingmaterial, any finish on the supporting surface 36 is protected from thedeleterious action of heat when the appliance I8 is being used.

The upper edge of wall 28 has formed thereon an inwardly extendingcurved flange 46 which terminates in an inwardly extending lip 48. Lip48 is adapted to receive and support a laterally and outwardly extendingflange 58 formed on the upper edge of a circumferentially extending wall52 of inner lining 22. As may be best seen in Figures 2 and 3 the-wall52 is substantially circular and is provided at the end thereof disposedopposite flange 58 with a circular bottom 54. The diameter of innerlining 22 is slightly less than the diameter of housing 24 whereby toprovide an annular-chamber 56 disposed between the outer side of thebottom and wall of inner lining 22 and the inner side of the bottom andwall of housing 24.

The upper side of flange 58 serves as a support for a laterallyextending flange 58 formed on the upper edge of the peripheral wall 68of the heating element support plate 28. The wall 68 is substantiallycircular and surrounds the body 62 of the support plate 28. A pluralityof apertures 63 are formed adjacent the periphery of body 62 and serve apurpose to be more fully described hereinafter. Body 62 is recessed inthe center thereof to provide a heating element accommodating support 64which is substantially circular in shape. The lower heating element I8is positioned concentrically on support 64 and is attached thereto bymeans of a plurality of sets of tines 66 which project through aperturesin support 64. A washer 68 receives the tines 66 on the underside ofsupport 64 and the tines are spread apart and bent over washer 68thereby to fasten the lower heating element I8 to support 64.

The heating element support plate 28, the inner lining 22 and theexternal husing'24 are held in assembled relationship as may be bestseen in Figure 5. Aligned apertures are formed in the center of each ofthe above members to receive therethrough a bolt I8 having threadedportions formed on either end thereof which extend through the aperturesin the support plate 28 and the housing 24. A nut I2 engages the threadof bolt I8 adjacent support plate 28 and a nut 14 similarly engages thethreaded portion of bolt I8 adjacent the housing 24. Bolt '18 incooperation with nuts I2 and 14 holds the support plate 28, the innerlining 22, and the housing 24 in assembled position to form a base. Ashas been explained above the inner lining 22 and the housing 24cooperate to form a chamber 56 therebetween. Support plate 28 and innerlining 22 similarly cooperate to form a chamber 16 which serves theimportant features described hereinafter.

Heating element I8 is of the usual type and includes a resistive elementI8 which is encased in a heat conducting cover 88. As may be best seenin Figure 5, heating element I8 is substantially rectangular in verticalcross section and has a height slightly greater than the distancebetween the support surface 64 and the plane of body 62 whereby theupper surface of heating element I8 is disposed a short distance abovethe plane of body 62. In plan view heating element I8 is circular withan aperture formed in the center thereof.

The heating element I8 is of the electrical resistive type and issupplied with potential and heating current through lines 82 and 84which are attached to suitable connections 86 formed on the lower sideof heating element I8 and which extend through the support surface 64.Heating current is supplied to lines 82-84 from a power line designatedby the numeral 88 through a thermostat unit of the usual type includinga temperature responsive element 88, an indicating light 92 and astructure for setting the thermostat device comprising a movable rod 84and an actuating knob 96. The thermostat is of the type which isnormally closed at low temperatures, that is, the temperature responsiveelement 98 is in position to complete the circuit from power line 88through the heating coil I8 at low temperatures, and the circuit isinterrupted or opened at high temperatures. When current is flowingthrough the heating element I8 the light 92 is lit. The temperature atwhich the thermostat opens can be adjusted by turning knob 96 thereby tomove the temperature responsive element 98 to the open position at alower temperature.

The temperature responsive element 98 and associated parts are mounteddirectly on the inner lining 22 bymeans of a screw 98. Direct thermalcontact between element 98 and inner lining 22 is thereby maintainedthrough screw 98. This construction insures that the thermostat isresponsive to any and all variations of the temperature of inner lining22. All of the parts of the thermostat with exception of knob 96 areenclosed within a housing I88 attached to one side of housing 24. As maybe best seen in Figure 3 a plurality of apertures I82 are formed in theupper side of housing I88 in such a position that the light radiatingfrom light bulb 92 is visible therethrough.

With the above structure in mind, one important use of the presentinvention can now be described. Cooking operations involving boiling,stewing, pan frying, and deep fat frying can be accomplished with theabove described structure by simply placing a cooking utensil such asthe pan I84 shown in dot and dash lines directly on the heating elementI8 as shown in Figure 5. Power is applied through line 88 and since theinner lining 22 is cool at the beginning of the cooking period, thethermostat will be closed and heating current will be applied to coilI8. It is desirable in the cooking operations set forth above to havethey maximum heat applied for a long length of time in order to bringthe heating medium such as water or grease to the required cookingtemperature. This is achieved since the apertures 63 in support plate 28allow adequate circulation whereby to keep the inner lining 22 cold.Since the temperature responsive element 88 is directly connectedthrough screw 98 to inner lining 22 the thermostat will be maintained inthe operative or heating position so long-as inner lining 22 is heldrelatively cold. After'a certain period of heating inner lining 22 willreach such a. temperature thatthe thermostat will open, thusdeenergizing heating coil I 6. Thereafter the thermostat willalternately close and open in such a manner as to keep the cookingappliance at the required cooking temperature as determined by thesetting of knob 06.

An important feature of the invention resides in the fact that acontinuous circulation of air is provided through chamber 56 due to thepresence of the two sets of apertures, namely, apertures 30 and 32formed in the bottom 26 and the side wall 28 respectively of housing 24.This continuous circulation of air serves to aid in the operation of thethermostat by providing a manner for ultimately cooling inner lining 22in case the heating element I8 should overheat. This circulation of airthrough chamber 56 also serves to maintain the external housing 24 at arelatively low temperature. This latter function serves to aid inprotecting the supporting surface 36 from the deleterious action of heatand also protects the user of the appliance from burns in the event thatthe user accidently contacts the outer wall of external housing 24.

Referring again to Figure 5 there is shown a cross section of the domeor cover I2 which forms a part of the present invention. Dome I2includes a slightly inclined and circularly extending side wall I06which is formed integral with a curved top I08. The lower edge of wallI06 is circular and is provided with a lower flange IIO which is adaptedto rest upon flange 58 of support plate 20 and to be confined by theflange 46 formed on the upper edge of housing 24. A handle H2 is affixedto the center of dome I2 by means of a bolt I I4 cooperating with a nutH6. The handle II 2 is preferably formed of a non-conducting material orheat insulating material such as wood, fiber, or plastic. The height ofthe side walls I06 of dome I2 is such as to accommodate various utensilswhich are used in baking, roasting, and broiling.

There are shown in Figure 5 the various parts of the present inventionassembled for use in broiling. During broiling the upper removableheating element I4 is attached to dome I2 in the position shown. Theupper heating element I4 includes a base I I8 upon which is disposed alength of exposed electrical resistance wire I20. Electrical potentialisapplied to the resistance wire I20 through a connection I22 whichextends through an aperture I24 in dome I2-. The heating element I4 isattached to dome I2 by means of the bolt I I4 which holds handle I I2 onthe dome. Bolt I I4 extends through an aperture in base I I8 and incooperation with wing nut I25 serves to hold the heating element I4 inthe position shown. A washer I28 is preferably disposed between base IIBand wing nut I26.

The material to be-broiled is placed upon a grate such as the grate I29shown in'dotted lines in Figure 5. Grate I29 isplaced within'a pan suchas pan I04, which serves to catch the juices and grease which fall fromthe material being broiled. Heating current is applied throughconnection 22 to the upper heating element I4, but preferably no heat isapplied from the lower heating element I8 while broiling. as will beunderstood by those skilled in the art. The heat from the open coil I20will be directed upon the material being broiled whereby to accomplishthis cooking operation. The thermostat is inoperative during broiling ifthe lower heating unit I6 is not used. I

Referring now to Figure 6 the manner in which roasting and baking areaccomplished using the present invention will be described. In theseoperations the heat spreader plate I6 is disposed over the heatingelement I8 whereby to remove the bottom of the pan I04 away from thesurface of the heating element I8. Spreader plate I6 includes a body I30which is generally circular and from which depends a side I32. Formed onthe lower edge of side I32 is a laterally and outwardly extending flangeI34 which rests upon flange 58 of the support plate 20 and within flange48 on the upper edge of housing 24. A plurality of apertures I 36 areformed in body I30 and are disposed in a circle near the peripherythereof. During roasting and baking the upper heating element I4 ispreferably removed and the dome I2 is positioned with its flange IIO ontop of flange I34 of spreader plate I6. The removal of heating elementI4 leaves aperture I24 in dome I2 open. Aperture I24, therefore, duringbaking and roasting, receives a temperature indicating device I38 as maybe best seen in Figure 4 of the drawing. Device I38 serves to indicatethe approximate temperature within the dome I2.

During roasting and baking a circulation of air is obtained from chamber16 up through apertures 63 in support plate 20 and apertures I36 inspreader plate I6 into dome I2 and back again. This circulation occurswhenever difierentials in temperature occur within the spaces. Suchcirculation tends to keep all portions in contact therewith atsubstantially the same temperature whereby to obtain even and uniformbaking and roasting. Due to this circulation the thermostat unit iseiTective to control the temperature in the upper chamber although thetemperature responsive element is directly connected to one of the wallsof the lower chamber. The temperatures in the upper and lower chamberswill be very nearly the same and in any event will be proportional toeach other. Accordingly, the thermostat unit can in effect control thetemperature in the upper chamber.

It is to be noted that circulation is obtained between the heatingelement I8 and the body I30 of spreader plate I6 whereby to preventoverheating of the bottom of utensil I 04. Heat is conserved duringroasting and baking operations due to the fact that the inner surface ofdome I2 is heat reflective and therefore tends to return radiated heatto the inner portions of the appliance. Due to the fact that theroasting or baking chamber is completely enclosed and due to thecirculation and heat reflection described above, a saving in energy usedduring baking and roasting is achieved since the thermostat begins tooperate shortly after the application of heating current to the heatingelement I8. More specifically, the inner lining 22 rapidly reaches theroasting or baking temperature and therefore opens the thermostat.

The circulation of air through chamber 56 which has been described aboveis also obtained during the baking and roasting operations. Accordingiythe finish of surface 36 is protected from excessive temperatures andthe outside of housing 24 is maintained at a relatively low temperaturethereby preventing the possibility of the user receiving burns bycontact therewith.

The manner in which the present invention is adapted for use with agrill plate for the direct frying of pancakes, hamburgers, and the like,is shown in Figure '7. A grill plate, generally desigt I42 and retainedthereon by the rim I44, ribs I48 serve to distribute the heat comingfrom heating element I3 throughout the surface of the objects andadvantages. has been provided an appliance which is adapted ..nated bythe numeral I40, is positioned directly :over the lower heating elementI8.

As is best shown in Figure 8, grill plate I40 is substantially .circularin shape and comprises a body M2, an

element I8, and a plurality of ribs I48 radiating .from a center pieceI50 to the flange I46. The

grease used in grilling is disposed on the body The grill plate I48. Theouter periphery of the grill plate I45 is supported on the flange 58 ofsupport plate 20 and is retained thereon by the flange 46 formed on theupper edge of housing 24. It will .be seen that the grill plate I40 canbe readily and easily placed in the grilling position and removed. Thedome I2, the heat spreader plate I6, the

heating element support plate 20, the inner lining 22, and the externalhousing 24 may be made of any suitable heat conducting material havingthe requisite mechanical strength. A preferred materials and methods offabrication may be used.

It will be seen that there has been provided a cooking appliance whichfulfills all of the above More specifically, there to be readily andeasily converted for use in various types of cooking operations. Animproved base has been provided which protects the supporting surfacefrom overheating and which prevents the user from being burned fromcontact therewith. An improved mounting for the thermostat unit isprovided whereby a better control of the cooking temperature of theappliance is obtained. During roasting and baking circulation of theheating medium is obtained around all portions of the utensil containingthe material to be roasted or baked whereby to achieve uniform andtherefore better roasting and baking.

Although a preferred embodiment of the invention has been shown forpurposes of illustration, it is to be understood that various changesand modifications can be made therein without departing from the scopeand spirit of the invention. Accordingly the invention is to be limitedonly as set forth in the following claims.

This invention is hereby claimed as follows:

1. A cooking appliance comprising an external housing, an inner liningof heat conducting material mounted in said housing and spaced therefromto form a chamber, a heating element support'mounted on said housing andcovering the upper end thereof, a heating element mounted on saidsupport, a heat spreader plate mounted on said housing above saidheating element and said inner lining being of a. size adapted to fitwithin said external housing with the flange on said inner lining beingsupported by the flange on said housing wall, a support overlying saidinner lining and supported on said flanges, said housing, inner lining,and support having aligned apertures formed therein, a bolt extendingthrough said apertures and clampingly holding the associated parts inassembled relation, a

heating element mounted on said support, said support having anotheraperture therein to provide for air circulation around said heatingelement and within said lining, and a thermostat mounted on said housingfor controlling said heating element, the temperature responsive elementof said thermostat being in thermal contact with said inner lining.

3. A cooking appliance comprising an external housing, said housingincluding a bottom and an upstanding wall formed around said bottom, theupper edge of said wall having an inwardly directed flange thereon, aninner sheet metal lining having an outwardly extending flange thereon,said inner lining being of a size adapted to fit within said externalhousing with the flange on said inner lining being supported by theflange on said housing wall, the bottom and walls of said housing beingspaced from said inner lining to provide a chamber therebetween, thebottom and wall of said housing having apertures therein to providecirculation between said chambers, a support overlying said inner liningand supported on said flanges, said housing, inner lining, and supporthaving aligned apertures formed therein, a bolt extending through saidapertures and clampingly holding the associated parts in assembledrelation, a heating element mounted on said support, said support havinganother aperture therein to provide for air circulation around saidheating element and within said lining, and a, thermostat mounted onsaid housing for controlling said heating element, the temperatureresponsive element of said thermostat being in thermal contact with saidinner lining.

4. A cooking aparatus for use in various cooking operations, andcomprising an external housing, an inner lining of relatively thin heatconducting material mounted within said housing and spaced inwardlytherefrom to provide a first chamber between the lining and the housing,a heating element support mounted on said housing and covering the openend of the inner lining to provide a second chamber between the supportand the inner lining, a heating element mounted on said support, athermostat mounted on said housing for controlling said heating elementand having the temperature responsive means thereof disposedsubstantially entirely within said first chamber and adjacent the outersurface of said inner lining, means providing direct thermal contactbetween saidgtempera- .ture responsive means and said inner lining, anda dome mounted on said housing and providing a third chamber between thedome and said heating element support, said support having an aperturetherethrough providing for circulation be tween the second and thirdchambers whereby the thermostat is substantially responsive to thetemperature in said third chamber, and said housing having aperturestherethrough for circulation of cooling air through said first chamberfor retarding heat responsive action of the thermostat.

5. A cooking apparatus asclaimed in; claim- 4,

wherein a heat spreader plate is disposed over said heating elementsupport and is provided with aperture means therethrough to assist thecirculation between the second and third chambers.

6. A cooking apparatus as claimed in claim 5, wherein the support andheat spreader plate are provided with peripherally disposed aperturesadjacent the outer edges thereof.

7. A cooking apparatus as claimed in claim 4, wherein the apertures insaid housing are arranged in upper and lower peripheral rows tofacilitate circulation of cooling air.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,029,230 Russell June 11, 1912 1,700,087 Slade Jan. 22, 1929Number Number

